Field of the Invention
The present invention relates to a communication recovery method using an isolator in a communication system through a power line, and more particularly, to a communication recovery method which can restore communication lines quickly in case of a disconnection or a short-circuit of the communication lines in the communication system for sensing and warning fire or gas in a large space such as an inside/outside of a ship or an inside/outside of a plant or a building.
Description of the Related Art
In order to sense and warn fire or gas in a large space such as an inside/outside of a ship or an inside/outside of a plant or a building, a smoke sensor for sensing generation of smoke, a temperature sensor for sensing surrounding temperatures, a flame sensor for sensing generation of flame, etc. have been provided, and systems for sensing generation of fire according to operation of the respective sensor have been used.
FIG. 1 schematically illustrates an overall configuration of a conventional fire generation sensing system.
Referring to FIG. 1, a conventional fire sensing and warning system, includes a first power supply A; a second power supply B; a direct current power supply C for emergency; a main control panel 10 for overall control of the system; a sensing device 20 including various sensors such as, a smoke sensor, a heat sensor, a complex sensor, a camera module unit, a VO unit, a conventional sensor, an addressable unit, a manual call point, a flame sensor, and an I.S barrier unit, and an alarm device for warning; a peripheral device 50 including a 8-channel standard relay and 8-channel programmable relay; a repeater panel 60 for the relay of various information to the main control panel 10; a sub-panel 40; and an interface unit 30.
FIG. 2 is a block diagram illustrating in detail a configuration of an interface unit in FIG. 1.
Referring to FIG. 2, various sensing devices 20 are connected to one communication loop 70. Specifically, the communication loop 70 is formed by at least two parallel lines 11 and 12 both ends of which are connected to the interface unit 30, and the lines 11 and 12 are connected to +terminal and terminal of devices including the sensor, respectively. Some examples of the sensing device 20, which may be connected to the communication loop 70, are a smoke sensor for sensing generation of smoke, a temperature sensor for sensing the temperature of a surrounding area, an emergency manual push switch which may be manually operated on emergency, a timer for counting a preset time, an alarm unit, and an I/O unit. When the interface unit 30 includes a plurality of loop cards, the communication loop 70 may be extended to a plurality of units, and a plurality of sensing devices may be connected to the communication loop 70 within an identifiable range. For example, if various devices such as sensors may be identified in the communication loop 70 by 7 bit signal, about 127 devices can be available. The interface unit 30 includes a loop 1-A terminal 31, a loop 1-B terminal 32, a communication interface 35, a power terminal 36, and an MCU 38 and may communicate with the main control panel 10 through the communication interface 35. Further, the interface unit 30 may be connected to the lines 11 and 12 which form the communication loop 70, and may receive a signal for controlling the sensing device 20 from the main control panel 10 and output it to a needed place. Further, the interface unit 30 may receive an electric current from the respective sensing devices 20, and then transmit it to the main control panel 10.
FIGS. 3(a) and 3(b) illustrate a method of using an isolator according to an embodiment of the present invention.
However, when the lines 11 and 12 forming the communication loop 70 are short-circuited or disconnected, sensors within the above range may not be operated.